Nitration of diaryl ethane



Patented Jan. 9, 1951 UNITED ESTATES 537,369 NI TRAT ION F DIARXL ETHANE, Ed ard Kropa, 01a Greenwich; andiJoIin I.

Roemer. Stamford, Conn.,j as signors;toAlmeri- I, can Gyanamid Company, New York, N. Y.,' a

corporation of'Maine 6N0 Drawing. Application- November 1948,. Serial No. 58,606

. (1 102). limes.-

Where R. 'hydrogenor a methyl group, an selected from the group consisting of zero, one and two and y is selected from the group consisting of one and two. They are prepared by any suitable nitration process such as, for example, that described for nitrating toluene on page 37 of the book Reactions of Organic Compounds by Hickinbottom.

The invention will be described in greater detail in conjunction with the following specific examples in which the proportions are givenin parts by weight. It should be understood, of course, that the examples are merely illustrative and that the scope of the invention should not be limited to the details therein set forth.

Example 1 36 parts of diphenyl ethane 108 parts of acetic anhydride 24 parts of copper nitrate trihydrate The diphenyl ethane is dissolved in the acetic anhydride and the copper nitrate trihydrate is added very slowly to the mixture which is maintained at 25-30" C. After all of the copper nitrate has been added, the reaction mixture is poured into waterancl an organic liquid layer separates. This i mononitro diphenyl ethane.

Example 2 20 parts of nitric acid (specific gravity 1.42) parts of concentrated sulfuric acid 45.7 parts of ditolyl ethane The nitric and sulfuric acids are mixed together and cooled, and the mixture is slowly added to the ditolyl ethane with stirring and suitable cooling to maintain the temperature at about 30 C. When all the acid has been added, the temperature is gradually raised to about C. and maintained at this point for about one hour. The reaction mixture is then cooled, the acid is removed, and the mononitro ditolyl ethane so obtained is washed successively with water, dilute sodium. carbonate solution, and

, tro gen content for 'mononitro ditolyl ethane is. 514' 4 Claims. (01. 230 645) more water." The, product so'obtained melts" at 11321114 C: and has" a nitrogen content of 5.47%. and 5.65% orrtwoanalyses: The theoreticaIni-' I Example 3 parts of concentrated nitrida'cid' 138 parts of concentrated sulfuric acid 7 parts of ditolyl ethane A mixtureof the concentratednitric acid and 92 parts of the sulfuric acid. is prepared. 15 parts of this mixture of acids are; then mixed with the; remaining 46' parts of concentrated sulfiiriic maane the resulting mixture is comedic about 0Cl The datum: ethane is added to this cooled. mixture; After reaction is complete'the reaction mixture is drowned in ice water, and the crystalline product which separates is filtered and recrystallized from acetone-alcohol solution. It has a meltin point of 191-194.5 C. and contains 14.18% and 14.44% nitrogen on two analyses. The theoretical nitrogen content for tetranitro ditolyl ethane is 14.36%.

Analogous nitro derivatives of dixylyl ethane and of mixed diaryl ethanes such as phenyl tolyl diethane, tolyl xylyl diethane, etc., are prepared by following the procedures of the examples.

The diaryl ethanes used in the examples may be readily prepared by reaction of the appropriate aromatic hydrocarbon, i. e., benzene, toluene, or xylene with acetaldehyde in the presence of hydrogen fluoride as described in U. S. Patent No. 2,439,228 or in the presence'of a mixture of hydrogen fluoride and fluosulfonic acid as described in the copending application of Woodrow Ernest Kemp, Serial No. 771,154 filed August 28, 1947. Moreover, if desired, one mol of benzene and one mol of toluene can be reacted with one mol of acetaldehyde according to either of the above processes in order to obtain the corresponding asymmetrical phenyl tolyl ethane which may alternatively be prepared by reacting styrene with toluene in the presence of sulfuric acid. The present invention contemplates mono-, di-, tri-, and tetra-nitro diphenyl ethanes, ditolyl ethanes, dixylyl ethanes, and the various mixed diaryl ethanes containing phenyl, tolyl or xylyl groups. The extent of nitration is, of course, controlled by varying the method of nitration, the strength of the nitrating agent, the temperature of nitration, the relative proportions of nitratin agent used, the duration of the nitration reaction, and the like.

The nitro derivat es. oi h pr s nt invention may be cracked catalytically in accordance with 2. 1,1-mononitroditolylethane having the fol-- processes such as those described in U. S. Patlowing formula:

ents Nos. 2,373,932; 2,420,688; 2,420,689; 2,422,163; CH3 CH8 2,422,164; 2,422,165; 2,422,169; 2,422,171; and CH3 2,422,318. The unsymmetrical compounds crack more readily .than do the symmetrical com- 5 I pounds. Thus, mononitro diphenyl ethane read- I N02 ily produces nitrostyrene.

The nitro derivatives of the present invention may be reduced to the corresponding amino com- 10 pounds. If a polynitro compound is the start- 0113 ing material, intermediate nitramines are formed.

By cracking the amino compounds, and particl ularly the unsymmetrical compounds such as monoamino diphenyl ethane, vinyl aniline may 4. 1,l-tetramtroditolylethane having the fol- 3. 1,1 mononitrodiphenylethane having the following formula:

be formed. Vinyl aniline or amino styrene, lowing formula: isomers are useful in the preparation of unsat- OH: 0113 urated isocyanates as described in the copending 1 (I333 I application of Edward L. Kropa, one of the presc Q ent inventors, and Arthur S. Nyquist, Serial No. ON I I N02 741,956, filed April 16, 1947, now U. S. Patent N02 N02 No.2,468,713. The amino compounds may also be diazotized and variously substituted by reac-v EDWARD P tion through the diazo group. Thus, they are JOHN ROEME'R t 1 t DELIN 180:1 2.5g: S111 ed to the production of dyestuffs REFERENCES CITED 1. A 1,1-nitr0dia y1ethgne having th f 110w- The following references are of record in the ing general formula: file of this patent:

R on: R 3 UNITED STATES'PATENTS Q-(fi-Q 0 Number Name Date R l H R 1,954,377 Calcott et al Apr. 10, 1934 (N02): 2 2,034,491 Sloan Mar. 17, 1936 where R is selected from the group consisting of FOREIGN PATENTS hydrogen and methyl groups, :1: 1s selected from the group consisting of zero, 1 and 2, and y is se- Numbel' Country Date lected from the group consisting of, 1 and 2. 39,381 Germany Apr. 14, 1887 

1. A 1,1-NITRODIARYLETHANE HAVING THE FOLLOWING GENERAL FORMULA: 